1. Field of the Invention
The present invention relates to the modification of resins such as usual resins, rubbers, waxes and oils. More specifically, it relates to methods useful to modify such resins, thereby improving properties such as flame retardancy, thermal stability, compatibility, surface properties such as adhesive properties, coating properties and dyeability as well as electrical properties of the resins, and it also relates to the applications of the modified resins.
2. Description of the Related Art
In general, resins are excellent in electrical properties, mechanical properties and workability, and so they have widely been used in many industrial fields as construction materials, electrical materials, vehicle, e.g., automotive materials, fiber materials, equipment materials and utensil materials.
However, these resins are extremely easily flammable, and keeping step with their extensive use, they have often become a predominant fire cause and a fuel source in the fire. Thus, the safety of the resins as the industrial materials has been strongly demanded. In addition, these resins are accompanied by some drawbacks. For example, the performance of flame retardancy, heat resistance and the like is poor; thermal stability is so practically insufficient as to easily deteriorate by heat, light and the like; and surface properties such as wettability, adhesive properties, coating properties and dyeability are poor, so that the applications of these resins are noticeably limited.
Furthermore, with the diversification of the applications of the resins, very high performances and characteristics have been required. However, in order to develop novel kinds of resins and to solve the respective problems in reply to this requirement, some technical and economical hurdles must be cleared. It has now been desired to improve and impart the performances of the resins without impairing their original characteristics, and so the development of new materials by the modification and combination of the resins is the extremely important theme in the industrial field.
A. Heretofore, as methods for improving and imparting the characteristics of a resin, there are known, for example, a method for providing a new kind of resin by the use of a new raw material, a novel synthesis technique, a novel polymerization technique and the like, and a method for modifying the resin with an already developed resin to improve and impart the various performances.
In the former method, it is practically difficult or technically very hard to create the new kind of resin which can meet the above-mentioned requirements, and another economical problem is also present.
On the other hand, the latter method has conveniences that the resin is easily available and the characteristics of the resin are already grasped, and the modification method, which comprises, for example, the introduction reaction of a functional group to the resin, is excellent in economical and technical points, and many suggestions regarding such modification methods have been made.
As one of the known modification methods, there is known a technique which comprises carrying out a modification reaction by the use of a reactant having the functional group, but for example, such a functional group is bonded only to a terminal position having a specific structure of the resin, or the amount of the functional group is noticeably limited. For these reasons, the accomplishment of the sufficient modification is difficult, and the modification or denaturation of the resin by the use of such a functional group is also hard. In a certain case, these modification methods are scarcely useful.
Furthermore, there is also known another modification method which comprises introducing the functional group to a resin such as a polyolefin resin having no functional group by the use of a reactant such as maleic anhydride or acrylic acid and a peroxide such as BPO together, and then carrying out a denaturation reaction using this functional group to modify the resin. This modification method has advantages that the functional group such as a carboxylic acid (anhydride) group which can easily be used for the modification or the secondary denaturation of the modification can be introduced and a preparation process is relatively easy, but this method is simultaneously accompanied by some disadvantages. For example, since the employment of the peroxide is required, the decomposition of the resin and the like occurs to noticeably lower the molecular weight of the resin and to bring about the coloring and quality change of the resin; it is difficult to introduce a large amount of the functional group, so that the modification of the resin is insufficient; thermal stability, heat resistance and the like deteriorate, and the functional group is separated off to noticeably accelerate the decomposition of the resin; and the polymerization and the like of the used reactant itself occurs to easily form reaction products, so that the physical properties of the resin easily deteriorate inconveniently.
Moreover, in this modification method, it is very difficult to introduce the functional group which is effective for the modification, performance impartment and the like, and thus a manner of adding a modifier having such a functional group can also be used. However, the employment of such a modifier inconveniently gives rise to the deterioration of the physical properties and characteristics of the resin.
The above-mentioned known modification methods are still impractical, and they are noticeably limited for technical and economical reasons.
The present inventors have intensively investigated with the intention of overcoming the above-mentioned drawbacks of the modification methods for resins, and as a result, it has been found that by reacting a resin with a compound quite different from compounds used in the known methods in structure and characteristics under specific reaction conditions, the resin can be successfully modified. According to this modification method, even if a large amount of the functional group is introduced to the resin, the molecular weight, physical properties and quality of the modified resin scarcely deteriorate; the amount of the functional group to be introduced can be selected in a wide range, and so the modification and performance impartment can easily be controlled; the use of a peroxide is not required, and hence the conditions of a modification reaction are moderate, a process is easy to conduct, and side reactions can be inhibited to prevent the decomposition and thus the quality change of the resin; since the functional group having an excellent modification and performance impartment power can be introduced and bonded to the resin without adding and mixing the compound having such a functional group, the physical properties of the resin are not impaired; even for the resin not having a functional group such as a carboxylic acid group, an amino group or a double bond group, the modification and performance impartment can be accomplished by the introduction of the functional group; the functional group which scarcely brings about the deterioration by heat or the like and which is capable of remarkably improving heat resistance can be introduced and bonded to the resin; and the functional group for improving properties such as flame retardancy, compatibility, surface properties such as wettability, adhesive properties, coating properties and dyeability, electrical properties, moldability and the like can be introduced and bonded to the resin to accomplish the modification and performance impartment. In consequence, a method for preparing the modified resin having the above-mentioned features can be provided.
In addition, it has also be found that when the modified resin obtained by the above-mentioned method is reacted with an epoxide under specific reaction conditions, an epoxy-modified resin can be obtained which is more excellent in surface properties such as wettability, coating properties, adhesive properties, dyeability and chemical resistance, electrical properties, moldability, compatibility and dispersibility with an other resin in addition to above-mentioned good features and which can be widely used for various modifications. In consequence, a method for preparing the epoxy-modified resin can be provided. On the basis of the findings of these preparation methods, the present invention has now been attained.
B. For the purpose of improving the flame retardancy of a resin, various methods have been suggested. For example, there have been suggested a method which comprises adding a flame-retardant to the resin, and a method which comprises using a flame retardancy-imparting material (inclusive of a halogen monomer) at the manufacture of the resin to incorporate the flame retardancy into the skeleton of the resin.
Among these techniques, the former method which comprises adding the flame-retardant to the resin has usually often been used, and examples of the known flame-retardant include halogen-containing compounds, phosphorus-containing compounds, inorganic compounds, nitrogen-containing compounds and the like.
When the halogen-containing compound is used as the known flame-retardant, the modified resin has some drawbacks. For example, heat resistance is usually poor; sublimation and bleeding tend to occur; an effect cannot be obtained in most cases, unless antimony trioxide is used together; and a large amount of an extremely toxic halogen-containing gas is generated in a fire. When the phosphorus-containing compound is used as the flame-retardant, the effect is insufficient if the compound is used singly, and the halogen-containing compound is often used together, so that the modified resins have the above-mentioned drawbacks. When the inorganic compound is used, the modified resin has some disadvantages. For example, an inorganic compound such as antimony trioxide is a rare substance of resources, and hence it is not easily available and there is also the problem of cost; in the case of aluminum hydroxide, the effect is weak and so it is necessary to add the same in large quantities, the specific gravity of the modified resin increases, the physical properties and moldability of the resin tend to deteriorate and the heat resistance of the resin deteriorates owing to contained water component. In addition, when the nitrogen-containing compound typified by triazine nucleus-containing compound is used, the modified resin has the following disadvantages. For example, sublimation, bleeding and the like tend to occur at molding; the manufacturing of the raw material is difficult, and the material cost is high; the physical properties and characteristics of the resin are liable to deteriorate owing to the added additive; the additive is lost with time, and the dispersability and miscibility of the additive also lowers, so that a flame-retardant effect noticeably decreases; and since a large amount of the additive is required to be added, the characteristics and physical properties of the resin are outstandingly impaired.
As the latter method, there is known a technique in which a material containing bromine, phosphorus or the like is incorporated as the flame retardancy-imparting material into the resin at the time of manufacturing. In this case, the loss, insufficient dispersion and the like of an effective flame-retardant component can be prevented, so that the reduction of the effect can be minimized, with the result that the physical properties, characteristics and the like of the resin can be easily advantageously maintained. However, this method has some inconveniences. For example, it is difficult to manufacture the flame retardancy-imparting material; a material cost is high; the acquisition of the flame retardancy-imparting material suitable for the manufacture of the resin is noticeably limited and can technically scarcely be obtained; it is very difficult or quite impossible to introduce and bond the flame retardancy-imparting material to the resin owing to the restriction on the manufacture of the resin, so that the desired resin can scarcely be provided; since the thermal stability of the flame retardancy-imparting material is poor, the thermal stability, heat resistance and the like of the obtained resin are poor; and a large amount of a toxic gas is generated in a fire.
These known flame-retarding methods for the resins are still insufficient and impractical, and they are noticeably limited for technical and economical reasons.
The present inventors have intensively investigated to overcome the above-mentioned drawbacks of the flame-retarding methods for resins, and as a result, it has been found that by using the modified resin or the epoxy-modified resin obtained by the above-mentioned method (A), the flame retardancy can be successfully imparted to the resin. According to this flame-retarding method of the resin, the modified resin is used in which a flame retardancy-imparting component is introduced and bonded to the resin, and therefore the dispersion and miscibility of the component can be achieved without any failure, whereby the flame retardancy of the resin can be remarkably improved; sublimation, bleeding and the like do not appear in contrast to the method which comprises adding a flame-retardant such as melamine; the production of char is extremely good, so that the sagging or dripping of oil droplets or a melt can be sufficiently inhibited; a toxic gas is scarcely generated; the excellent characteristics and physical properties of the resin are not impaired; even to the resin to which the flame retardancy-imparting component is scarcely introduced and bonded in a manufacturing process, the functional group regarding the flame retardancy-imparting component can be easily introduced and bonded; such a functional group can be introduced after the manufacture of the resin, and so the resin can be easily manufactured at a low cost. In consequence, an excellent flame-retarding method of a resin can be provided. In addition, it has also been found that when the above-mentioned modified resin is used together with phosphoruses, an isocyanuric acid, a cyanuric acid or an amino group-containing compound, the resin having the further improved flame retardancy can be successfully obtained. In consequence, a more excellent flame-retarding method of a resin can be provided. On the basis of these findings, the present invention has now been attained.
C. Usually, resins tend to become brittle, or are liable to bring about decomposition or coloring owing to the application of external energy such as heat or light, or owing to the presence of oxygen or a heavy metal. Thus, the long-term heat resistance and weathering resistance of the resins are poor, and stability at heating is bad, so that moldability is largely limited. Therefore, in order to improve moldability and workability, it is necessary to blend the resin with another resin, and this blending results in the deterioration of the characteristics and physical properties of the resin. For this reason, the blending method is limited, though the resin has the excellent characteristics. Heretofore, various techniques for improving the blending method have been suggested, but they are still insufficient to overcome the above-mentioned faults. In an extreme case, even the excellent characteristics of the resin are lost, and some of the suggested techniques cannot be utilized at all.
As an example of conventional thermal stabilization methods, there has been suggested a thermal stabilization method of a resin composition which comprises adding, to the resin composition, a thermal stabilizer such as a benzoate, an amine, an arylphosphondiamide, an organic phosphite, a hindered phenol, melamine, benzoguanamine, phthaloguanamine or spiroquanamine (e.g. Japanese Patent Publication No. 47739/1976).
However, the resins obtained by this thermal stabilization methods have the following drawbacks. That is to say, ultraviolet light resistance and weathering resistance are poor, and color change also noticeably occurs; when molding is carried out at a high temperature, coloring, the color change and the like also noticeably occur; a thermal stabilization effect is still insufficient; the thermal stabilizer itself easily gives rise to thermal decomposition at the time of the working and the thermal stabilization effect is very low, and for the resin which will be subjected to the high-temperature molding, any effect cannot be exerted; and the effect of the thermal stabilizer is very low owing to dispersion failures such as the loss and bleeding of the added and mixed thermal stabilizer with time, and in an extreme case, the effect is all lost. In consequence, this thermal stabilization method of the resin is still insufficient and impractical, and its utilization is noticeably limited for technical and economical reasons.
In view of the above-mentioned defects of the thermal stabilization method of the resins, the present inventors have intensively investigated. As a result, it has been found that by using the modified resin or the epoxy-modified resin obtained by bonding and introducing the specific functional group in accordance with the above-mentioned preparation method (A), the resin can be successfully thermally stabilized. According to this thermal stabilization method of the resin, ultraviolet light resistance, weathering resistance, thermal stabilization and heat resistance can be noticeably improved; since a thermal stabilization-imparting component is bonded and introduced to the resin, the dispersion and miscibility of the component can be achieved without any failure, and so the effect of the stabilization is very high; the deterioration of the resin can be inhibited even when the resin is used at a relatively high temperature for a long period of time, and the resin itself is difficult to decompose even at the high temperature, so that the long-term heat resistance is excellent; since the thermal stabilization-imparting component is scarcely lost, so that the thermal stabilization effect scarcely deteriorates, and the handling properties, physical properties and characteristics of the resin can be sufficiently maintained; the decomposition and deterioration of the resin by ions of a heavy metal such as copper can be remarkably inhibited; even when molding or working is carried out at a high temperature, the heat deterioration, coloring and color change of the resin can be inhibited; and temperature for 5% weight reduction of the resin at heating can be remarkably improved, so that the thermal stability and heat resistance of the resin can be sufficiently enhanced and the high-temperature molding or working is extremely easy, and for example, for polyphenyleneether resins and the like in which the high-temperature moldability or workability is noticeably limited by a conventional technique, a moldability improver or the like is unnecessary, with the result that a new material having excellent physical properties and characteristics can be provided at a low cost. In consequence, an excellent thermal stabilization method of the resins can be provided. On the basis of the finding of this stabilization method of the resins, the present invention has now been attained.
D. Usually, resins possess excellent characteristics and have been widely used in many industrial fields, but as resin modification techniques for improving various performances and imparting a new performance without impairing the characteristics of the resin, various polymer alloy formation methods have been suggested.
Heretofore, as the polymer alloy formation method of a resin, there have been suggested a method which comprises modifying the resin itself to impart the performance to the resin, and a method which comprises adding a third component such as a compatibilizer to the resin.
The former method is useful which permits the easy formation of the modified resin having not only excellent compatibility and solubility but also the uniform performance. However, this method has some drawbacks. For example, the modification reaction of the resin is difficult to carry out, and the characteristics of the modified resin tend to deteriorate because of the molecular weight reduction, coloring and color change of the resin at the modification. On the other hand, the latter method has the following disadvantages. That is to say, the heat resistance, weathering resistance, water resistance and characteristics of the obtained resin deteriorate owing to the presence of the contained third component; the manufacturing process of the compatibilizer is complex, and a manufacturing cost of the compatibilizer is high; it is difficult to obtain the resin having the uniform performance, because of the dispersion failure of the third component; and it is also difficult to obtain the resin having improved physical properties and characteristics.
The present inventors have intensively investigated to overcome the above-mentioned defects of the compatibilization method of a resin, and as a result, it has been found that by using the aforesaid modified resin or epoxy-modified resin obtained by the above-mentioned method (A), different kinds of resins can be successfully compatibilized. According to this compatibilization method of resins, the compatibilization between different kinds of resins and the solubility of the resins are excellent; the heat resistance, weathering resistance, water resistance, chemical resistance and the like of the obtained resin are also excellent; and the resin can easily be manufactured at a low cost. In consequence, an excellent compatibilization method of resins can be provided. On the basis of this knowledge, the present invention has now been attained.
E. Usually, resins are excellent in characteristics such as electrical properties, mechanical properties and moldability, and so they have been widely used in many industrial fields, but with the diversification and enhancement of their applications, it has been strongly desired to improve the characteristics of resins by combination with a different kind of material. It has been an industrially important theme to improve surface properties such as the coating properties on the surface of the resin, the adhesive properties of the resin to another kind of material, wettability, dyeability, water/oil repellency and solvent resistance, and electrical properties such as chargeability and conductivity, and it has been another theme to develop a coating resin composition and an adhesive resin composition useful for such materials.
Heretofore, as methods for modifying the surface of the resin, there has been suggested a surface modification method utilizing an oxidizing agent and corona discharge, and another surface modification method which comprises adding an additive to the resin. In the former method, since a surface treatment is carried out after the molding or the like, a treatment procedure is noticeably troublesome; it is difficult to do the surface treatment on molded articles having various shapes; and a modification effect is not practically sufficient. In the latter method, since the additive is lost with time, the effect of the additive noticeably lowers in a short term; and the compatibility of the resin with the additive as well as the solubility of the additive in the resin is poor, so that the sufficient surface modification effect cannot be obtained. These surface modification methods of the resin are still practically insufficient, and the utilization of these methods is noticeably limited for technical and economical reasons.
The present inventors have intensively investigated with the intention of overcoming the above-mentioned defects of the surface modification methods of a resin, and as a result, it has been found that by using the modified resin or the epoxy-modified resin obtained by the above-mentioned method (A), the surface of the resin can be successfully modified. According to this surface modification method of a resin, surface properties such as wettability, coating properties, adhesive properties, dyeability, water/oil repellency, and electrical properties such as chargeability and conductivity of the resin can be remarkably improved; since the resin itself can be modified, so that the modified resin is excellent in high-temperature stability and non-volatility, and the diminution of the effect due to the loss of a surface-modifying component does not take place; the surface modification can be uniformly achieved on molded articles having various shapes; and there can be sufficiently modified a polyolefin resin such as a polypropylene resin and a polyolefin fiber in which surface properties such as adhesive properties, coating properties and dyeability are noticeably limited. In consequence, an excellent surface modification method of a resin can be provided. In addition, it has also been found that a coating resin composition and an adhesive resin composition can be provided which are extremely useful for resins and which comprises the above-mentioned modified resin or epoxy-modified resin. On the basis of these findings, the present invention has now been attained.